An objective of pistachio breeding programs is to develop new varieties that can be harvested at unique times relative to other pistachio varieties. The female pistachio variety ‘Kerman’ (not patented) is the main later-season pistachio cultivar grown in California and in other parts of the world, but other female pistachio varieties are also grown, such as ‘Golden Hills’ (U.S. Plant Pat. No. 17,158). A major problem for pistachio growers that has developed with the rapid increase in pistachio plantings in California, for example, is the availability of harvest equipment/contractors and processing capacity, since most of the existing crop (‘Kerman’) matures at about the same time. The pistachio industry has ˜40% of its orchards in non-bearing status, yet plantings have not slowed. Difficulty finding both harvesting equipment and people to run them at harvest time is a problem for pistachio growers. The industry-wide harvest window is short because of the large amount of future-bearing ‘Kerman’ plantings, all of which mature at about the same time. Nut processing facilities will likely need to greatly increase their capacity to handle this large increase in nuts, yet will use this increased capacity for a very short time period.
Further, ‘Kerman’ appears to be vulnerable to lack of winter chill, as shown directly through erratic bloom and indirectly from lack of overlap with this variety's pollenizer, ‘Peters’ (not patented). Low chill years have presented great difficulties for pistachio growers in the lower San Joaquin valley of California during periods when chilling was well below the minimum needed for synchronous flower development in ‘Kerman’. High levels of “blanking” and non-splits were observed.
‘Golden Hills’ has become a popular alternative to ‘Kerman’ because it can be harvested before ‘Kerman’. However, it would be advantageous to have additional varieties that can be harvested even earlier than ‘Golden Hills’ to increase the availability of pistachio harvesting equipment and processing capacity, as well as to have different pistachio varieties available that can be harvested in a maturity series. Developing a harvest date series is an optimal way to use existing harvest equipment/contractor and processing plant resources. Without staggered harvest dates, the pistachio industry will have to develop significantly increased (e.g. 2×) harvesting capability (which is now provided by custom harvestors) and find investors willing to fund new processing plants (which are only used for a few weeks per year). Failure to develop these facilities or alternatively, a harvest date series, will expose the industry to significant risk from aflatoxin contamination in the crop due to extended pre-processing times.
Thus, there exists a need for improved pistachio varieties with earlier harvest dates than the present industry standards. The present female pistachio variety ‘Gumdrop’ described herein is a product of the breeding efforts to produce improved pistachio varieties.